Total Life Approach for Fatigue Life Estimation of Welded Structures

AbstractIt was shown that estimation of fatigue lives of welded joints can be successfully carried out by considering the fatigue process as a fatigue crack growth from the initial intrinsic crack size of a0=ρ* until the final crack af. Such an approach avoids a somewhat arbitrary division of the fatigue process into the crack initiation and propagation and concentrates on using only one methodology - the fracture mechanics theory. The stress intensity factors can be determined in such cases by the weight function method. The proposed methodology allows estimation of the fatigue life under both constant and variable amplitude loading

Kappa-deformed Snyder spacetime

We present Lie-algebraic deformations of Minkowski space with undeformed Poincare algebra. These deformations interpolate between Snyder and kappa-Minkowski space. We find realizations of noncommutative coordinates in terms of commutative coordinates and derivatives. Deformed Leibniz rule, the coproduct structure and star product are found. Special cases, particularly Snyder and kappa-Minkowski in Maggiore-type realizations are discussed. Our construction leads to a new class of deformed special relativity theories.Comment: 12 pages, no figures, LaTeX2e class file, accepted for publication in Modern Physics Letters

Global One-Dimensionality conjecture within Quantum General Relativity

The simple quantum gravity model, based on a new conjecture within the canonically quantized 3+1 general relativity, is presented. The conjecture states that matter fields are functionals of an embedding volume form only, and reduces the quantum geometrodynamics. By dimensional reduction the resulting theory is presented in the form of the Dirac equation, and application of the Fock quantization with the diagonalization procedure yields construction of the appropriate quantum field theory. The 1D wave function is derived, the corresponding 3-dimensional manifolds are discussed, and physical scales are associated with quantum correlations.Comment: 16 pages, no figures, to appear in Gravitation and Cosmolog